Article
Geosciences, Multidisciplinary
V Mergner, I Kupenko, G. Spiekermann, S. Petitgirard, L. Libon, S. Chariton, M. Krug, R. Steinbruegge, I Sergueev, C. Sanchez-Valle
Summary: Studies suggest that FeSi formed from core-mantle chemical reactions may be a plausible source of ultralow-velocity zones (ULVZs) at the core-mantle boundary (CMB). The low sound velocities of FeSi compared to other candidate phases in a lowermost mantle assemblage could explain the velocity decrements and high density anomalies observed in a wide range of ULVZs with less than 8.4 vol% of FeSi in the aggregate.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geosciences, Multidisciplinary
Surya Pachhai, Mingming Li, Michael S. Thorne, Jan Dettmer, Hrvoje Tkalcic
Summary: Studies reveal that ultralow-velocity zones beneath the Coral Sea exhibit stratified density increases and shear-wave velocity decreases, which may be related to remnants of Earth's early differentiation.
Article
Geochemistry & Geophysics
Jonathan Wolf, Maureen D. D. Long
Summary: The study reveals that ultralow velocity zones (ULVZs) and seismic anisotropy are commonly detected in the lowermost mantle at the edges of large low velocity provinces (LLVPs). By jointly investigating ULVZ structure and lowermost mantle anisotropy near the Pacific LLVP, the study provides insights into the geodynamic scenarios for flow in the deep mantle. The findings contribute to our understanding of mantle flow processes at the edges of LLVP structures.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2023)
Article
Geochemistry & Geophysics
Justin Krier, Michael S. Thorne, Kuangdai Leng, Tarje Nissen-Meyer
Summary: The study analyzed and modeled seismic data from the Samoa ultralow-velocity zone, finding the need for a large single ULVZ to explain the data and inferring the elastic parameters of the ULVZ. Velocity reductions are associated with the composition of the ULVZ, and geodynamic predictions for a mobile compositional ULVZ support the findings of the study.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Nanoscience & Nanotechnology
Sandip Thakur, Ashutosh Giri
Summary: Metal halide perovskites have attracted significant attention due to their remarkable structure-property relationships. Contrary to conventional belief, our atomistic simulations show that the enhancement in thermal conductivity is not due to guest ions' rattling behavior in the framework. Instead, the ultralow thermal conductivities primarily originate from the anharmonic and mechanically soft metal halide framework. Manipulating framework anharmonicity through strain and octahedral tilting is an efficient strategy to control heat transfer efficacy.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Multidisciplinary Sciences
Matt J. Jones, Alexander J. Evans, Brandon C. Johnson, Matthew B. Weller, Jeffrey C. Andrews-Hanna, Sonia M. Tikoo, James T. Keane
Summary: Numerical simulations demonstrate that the mantle convection caused by the South Pole-Aitken impact can explain the existence of the nearside-farside lunar asymmetry.
Article
Chemistry, Multidisciplinary
Xiao Ma, Haijun Bin, Bas T. T. van Gorkom, Tom P. A. van der Pol, Matthew J. J. Dyson, Christ H. L. Weijtens, Marco Fattori, Stefan C. J. Meskers, Albert J. J. M. van Breemen, Daniel Tordera, Rene A. J. Janssen, Gerwin H. H. Gelinck
Summary: Organic bulk heterojunction photodiodes (OPDs) are attracting attention in sensing and imaging. The detectivity of these OPDs is often limited by a substantial reverse bias dark current density (J(d)). Recent studies have shown that thermal charge generation mediated by mid-gap states is responsible for J(d). The temperature dependence of J(d) in state-of-the-art OPDs is reported in this study, and it is found that the dark current is attributed to thermal charge generation at the donor-acceptor interface mediated by intra-gap states near the band edges.
ADVANCED MATERIALS
(2023)
Article
Multidisciplinary Sciences
Samantha E. Hansen, Edward J. Garnero, Mingming Li, Sang-Heon Shim, Sebastian Rost
Summary: Using a new seismic analysis approach, researchers have identified widespread and variable ultralow velocity zones (ULVZs) beneath a largely unsampled area in the Southern Hemisphere. Their study suggests that the accumulation of previously subducted materials on the core-mantle boundary (CMB) could explain the origin of ULVZs, and that these subducted materials can be globally distributed throughout the lowermost mantle with varying concentrations. The discovery provides insights into the distribution and characteristics of ULVZs.
Review
Environmental Sciences
Saskia Goes, Chunquan Yu, Maxim D. Ballmer, Jun Yan, Robert D. van der Hilst
Summary: This review discusses the characteristics of seismic discontinuities in the mantle transition zone (MTZ) and their impact on mantle convection. The study finds that the topography of seismic discontinuities mainly reflects variations in mantle temperature and shows features of mantle flow. However, there is incongruity in the thermal structure across the MTZ in different regions, leading to delayed transport of cold and hot material in convection. Additionally, seismic results reveal lateral and vertical heterogeneity in major element chemistry and volatile content in the MTZ.
NATURE REVIEWS EARTH & ENVIRONMENT
(2022)
Article
Physics, Particles & Fields
Arunava Bhadra, Souvik Ghose, Biplab Raychaudhuri
Summary: There is currently no consensus in the literature on the origin of the relativistic Sagnac effect. Recent experiments have questioned the pivotal role of rotation in this effect and suggested that the asymmetric position of the observer with respect to the light paths is the cause.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Geochemistry & Geophysics
Surya Pachhai, Michael S. S. Thorne, Sebastian Rost
Summary: A hierarchical Bayesian inversion method was developed to invert ScP waveforms from multiple events simultaneously, considering path attenuation and correlated noise. The method was applied to data recorded in Australia, showing the presence of approximately 12 km thick ULVZ with a reduction of about 14% in S-wave velocity, and greater variability in ULVZ properties in the south compared to the north.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Materials Science, Multidisciplinary
T. Pandey, Mao-Hua Du, David S. Parker, L. Lindsay
Summary: Inorganic lead-free halide double perovskites exhibit non-toxic and stable optoelectronic properties, as well as large thermoelectric potentials and high carrier mobilities, making them promising for thermoelectric applications.
MATERIALS TODAY PHYSICS
(2022)
Article
Multidisciplinary Sciences
Ivan de la Cruz Vargas-Cordero, Lucia Villar-Munoz, Umberta Tinivella, Michela Giustiniani, Nathan Bangs, Joaquim P. Bento, Eduardo Contreras-Reyes
Summary: The Central-South Chile margin is a key location to study changes in the gas hydrate system, but the dynamic of the gas hydrate/free gas system in the region is currently unclear. Research findings show high concentrations of hydrate/free gas and local anomalies in geothermal gradients, related to fluid migration through faults associated with seafloor mud volcanoes.
SCIENTIFIC REPORTS
(2021)
Article
Geochemistry & Geophysics
Renqiang Liao, Hongli Zhu, Congying Li, He Liu, Weidong Sun
Summary: The iron isotope heterogeneity of subduction-related primitive magmas is primarily caused by mantle melting processes. Additionally, the varied iron isotope compositions in subduction settings may reflect their heterogeneous sources, which may be related to plate subduction.
Article
Engineering, Electrical & Electronic
Yuan Ren, Song Qiu, Tong Liu, Zhengliang Liu, Wei Cai
Summary: This article presents a technique for rotational speed measurement based on the non-contact optical method using superposition vortex light. The ultralow rotational speed as low as 0.001 r/s can be accurately measured with high accuracy using this method. The detection system has a simple structure and non-contact features, allowing near real-time speed acquisition. Experimental results are in good agreement with the theoretical value, filling the gap in ultralow rotational speed measurement.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2022)
